Recent copending applications by the inventor, incorporated by reference are as follows:
1. Ser. No. 348,803 "Method and Apparatus for Automatically Handling Assembly on Moving Objects" ("Targets") now U.S. Pat. No. 4,654,949 PA0 2. Ser. No. 453,910 "Robot Calibration" PA0 3. Ser. No. 592,443 "Robots and Manipulator Arms" PA0 4. Ser. No. 323,395 "Robot Tractors" now U.S. Patent No. 4,482,960 PA0 5. Robot Tractors, Vehicles, and Machinery (Ser. No. 651,325) PA0 1. Scan the total part image and find the holes. Once the holes are found, determine the shape of the hole, the size of the hole, or the relative locations of the holes; confining analysis to those holes which are to be considered as targets. PA0 2. Clearly, the above is probably the way to go in many cases. However, another clear case is where the boundaries of the part such as the edges of a basically rectangular cylinder head are known. Having found the edges of the part, one can immediately segment the image into sections and simply scan for holes in certain areas of the field of view. It is likely on a well manufactured part such as a cylinder head, that one could almost immediately go to the zone on which the desired holes were located and simply confirm that they are of roughly the right diameter so as to act as the target holes.
These applications disclose novel means for achieving high accuracy, high speed and potentially low cost robot vision in up to 6 degrees of freedom using targets affixed on, or forming part of, an object. In particular, these applications disclose that it is desirable to construct a control system for a robot which can use certain features of an object to provide an accurate solution of a photogrammetric equation to allow up to 6 degrees of freedom determination of part location in space with a single camera or multiple cameras.
In the automotive industry particularly, holes in parts are natural features which generally have a precise dimensional relationship to the object as a whole. The reason for this is clear. Most of the holes are used for mounting the object to something else and in that case have to be in the proper position or the object itself will be out of position when so mounted. Examples of this include body panels, instrument panels, water pump covers, radiator brackets, etc.
In other cases, holes are there to allow the assembly of the part together with other parts for functional or decorative purposes. These could include rocker cover rail holes, rocker stud holes and cylinder heads, engine cylinder head bolt holes, various frame holes and the like. In short, a vast number of the parts of cars, appliances, aircraft and other things have holes as their principle feature. And in almost cases, these holes have been either molded, cast, machined or otherwise incorporated into the part in such a way as to be in a dimensionally accurate location, at lease accurate enough for the purpose of picking the part, working on it, handling it or what have you.
In Ser. No. 348,803 (Targets) previously filed, it was disclosed that the natural occurring holes in the part could be used as the targets. This is further elaborated on herein.